Abstract:By method of Petri dish bioassay and biochemical analysis,the allelopathy mechanism of juglone were researched through effect-testing of juglone with different concentrations on seed germination and seedling growth of wheat.The results indicated that:(1)The low concentration (4 and 20 μmol·L-1) of juglone has high hasten effect on seed germination and seedling growth,which promoted the content of soluble protein and decreased the content of malondiadehyde (MDA) and the activity of superoxide dismutase (SOD).(2)With the concentration of juglone increasing (100~1 250 μmol·L-1),the activity of SOD of wheat was firstly increased and then decreased,and the content of MDA was getting higher.Besides,the α-amylase activity and the content of soluble protein and the relative water content were declined.(3)Under 1 250 μmol·L-1 juglone treatment,cells were degraded gradually,cell structure was in disorder and had a severe twist,vascular bundle was disappeared,cell walls had a twist with slight plasmolysis,chloroplast was damaged and reduced,while cell nucleus were damaged.In summary,with the increasing concentration of juglone,the allelopathy effect was raised.The degree of membrane lipid peroxidation was strengthened and the activities of protective enzymes and seed germination and seedling growth were inhibited.